You ignored August 12th  didn’t you?

That’s when the world celebrates National Middle Child Day every year, but you ignored it just as you have ignored us “middles” our entire lives!

I’m the third-born child in a family of six — an only boy with five sisters.

As a tyke I longed for the acceptance of my older sisters. At times, they doted over me but other times they were repulsed by their stinky, sweaty baby brother who always had a nose full of boogies.

I was permanently banished to the back seat of our station wagon, which faced the rear window, and which is why I spent most of my childhood in a state of motion sickness.

When my sisters were teeny boppers, they, like all girls in America, were infatuated with pop singer David Cassidy.

Since he sported a shag haircut — he parted his hair down the middle and feathered it over the sides of his noggin — they were determined that I get one, too.

I became the first kid in St. Germaine Catholic School to do so and by the end of the school year every single boy had the David Cassidy cut.

When my three younger sisters arrived, and as my older sisters started doing their own things outside the family unit, I evolved into the older brother and finally was treated with a little respect.

The experience I had as a middle child in the ‘70s is one that few kids experience today — mainly because there are so few large families today.

In our neighborhood, a small ‘70s family had three kids, but most families had four to six and a few had more than 10.

Now, with both parents working and the cost of raising children considerably higher than it was 40 years ago, most parents prefer to have one or two kids, according to The CUT.

For several reasons, this trend is not good for the rest of us.

The unique characteristics of a middle child are honed by his or her experiences in the family pecking order.

For starters, we are good mediators.

In my family, I always disliked seeing my siblings arguing and always sought to moderate and quell them — and I still do. I’m happiest when we are all getting along.

The International Business Times reports that because middle children “are more willing to compromise and look at all sides of a question,” they turn out to be excellent negotiators compared to first-born or last-born children.

Is the lack of middles one of the unheralded causes of eroding civility? Could be.

I’d also argue that we middles have a highly refined sense of humor — which is also beneficial to our national health and well-being.

Humor is how we got attention. Using comic relief is also how we calm everyone down in stressful times and improve the discourse and the general happiness of our friends and family.

I’ve long thought that first-borns and last-borns are generally the most focused and ambitious family members who go on to become leaders in their chosen fields, but I was surprised to learn that half of our presidents were middle children, according to Business Insider.

Joe Biden is the oldest of four, so he probably doesn’t know how to use the most powerful middle-child negotiating tactic to neutralize his opponents: threaten to use their toothbrushes!

Tom Purcell is an author and humor columnist for the Pittsburgh Tribune-Review. Email him at Tom@TomPurcell.com.